1. Field of the Invention
The present invention relates to a ratchet wrench and, more particularly, to a ratchet wrench with a switch for changing a driving direction thereof.
2. The Prior Arts
Taiwan Patent Publication No. 373543 entitled “RATCHET WRENCH STRUCTURE WITH ANGLE-CHANGEABLE SINGLE DIRECTION COUPLING” discloses a ratchet wrench including a body having a head and a handle interconnected to the head at an angle of 15°. The head includes a compartment receiving a gear wheel and a pawl. A retaining ring includes a tang fixed in a hole of the pawl. The retaining ring further includes two engaging grooves opposite to the tang. A switch has a portion pivotably mounted in an end of the compartment and pivotable between two operative positions. A peg mounted in the body is selectively engaged with one of the engaging grooves to retain the retaining ring in place. Pivotal movement of the switch causes sliding movement of the pawl via the retaining ring to change the driving direction of the ratchet wrench. However, the retaining ring made of a wire is liable to deform after a period of time, such that the pawl can not be moved to the desired position, leading to adverse affect to the function of the ratchet wrench. Furthermore, a peg is required in the body to retain the retaining ring in place. The overall structure is complicated and requires troublesome and time-consuming assembly, resulting in an increase in the manufacturing costs. Furthermore, although such a ratchet wrench can drive fasteners such as bolts, nuts, etc. in either of clockwise and counterclockwise directions while allowing free rotation in a reverse direction, the ratchet wrench can not be utilized as a conventional wrench of the type capable of driving fasteners in either direction and not allowing free rotation in the reverse direction, which may be required in some cases. As an example, when it is desired to proceed with slight tightness adjustment of a fastener by rotating the fastener in the tightening direction and/or loosening direction before the desired tightness is obtained, a user has to frequently move the switch between two operative positions to change the driving direction of the ratchet wrench, which is time-consuming and laborsome.
Thus, a need exists for a ratchet wrench with a simplified structure while allowing reliable operation as well as slight tightness adjustment.